C1q/Tumor necrosis factor-related protein-3 protects macrophages against LPS-induced lipid accumulation, inflammation and phenotype transition via PPARγ and TLR4-mediated pathways

FOXQ1 inhibits the progression of osteoarthritis by regulating pyroptosis

BACKGROUND

Osteoarthritis (OA) is the most common age-related joint disease, and the NLRP3-induced pyroptosis has been demonstrated in its progression. The upstream molecules or specific mechanisms controlling NLRP3 and pyroptosis in OA remain unclear.

METHODS

Transcriptome sequencing was performed in the OA mice model, and the expression levels of differentially expressed genes were assessed by qRT-PCR. The cell model was constructed by IL-1β-induced ATDC5 cells. The cell proliferation was examined using CCK-8 assay, and apoptosis was tested using flow cytometry. Western blot was used in protein inspection, and ELISA was used in inflammatory response evaluation.

RESULTS

Compared with the control group, there were 229 up-regulated and 32 down-regulated genes in model group. We detected that FOXQ1 was down-regulated in the OA mice model, improved proliferation, and restrained apoptosis of chondrocytes. Over-expression of FOXQ1 could inhibit pyroptosis-related proteins and inflammatory cytokines, containing NLRP3, Caspase-1, GSDMD, IL-6, IL-18, and TNF-α, and in contrast, FOXQ1 silencing exerted the opposite trend.

CONCLUSIONS

FOXQ1 may inhibit OA progression via down-regulating NLRP3-induced pyroptosis in the present study.

Clinical Significance of Serum CTRP3 Level in the Prediction of Cardiac and Intestinal Mucosal Barrier Dysfunction in Patients with Severe Acute Pancreatitis

C1q/tumor necrosis factor-related protein 3 (CTRP3) has been demonstrated to play a protective role in mice with severe acute pancreatitis (SAP). However, its clinical significance in SAP remains unknown. This study was conducted to explore the clinical values of serum C1q/tumor necrosis factor-related protein 3 (CTRP3) level in the diagnosis of cardiac dysfunction (CD) and intestinal mucosal barrier dysfunction (IMBD) in SAP. Through RT-qPCR, we observed decreased CTRP3 level in the serum of SAP patients. Serum CTRP3 level was correlated with C-reactive protein, procalcitonin, creatine, modified computed tomography severity index score, and Acute Physiology and Chronic Health Evaluation II score. The receiver-operating characteristic curve revealed that CTRP3 serum level < 1.005 was conducive to SAP diagnosis with 72.55% sensitivity and 60.00% specificity, CTRP3 < 0.8400 was conducive to CD diagnosis with 80.49% sensitivity and specificity 65.57%, CTRP3 < 0.8900 was conducive to IMBD diagnosis with 94.87% sensitivity and 63.49% specificity, and CTRP3 < 0.6250 was conducive to the diagnosis of CD and IMBD co-existence with 65.22% sensitivity and 89.87% specificity. Generally, CTRP3 was downregulated in the serum of SAP patients and served as a candidate biomarker for the diagnosis of SAP and SAP-induced CD and IMBD.

Clinical Diagnostic Values of C1q/TNF-Related Protein-3 for Polycystic Ovary Syndrome Women with Insulin Resistance

Polycystic ovary syndrome (PCOS) is the most common disease caused by complex endocrine and metabolic abnormalities in women. Insulin resistance is considered an important pathophysiological factor in the pathogenesis of PCOS. Here we investigated the clinical values of C1q/TNF-related protein-3 (CTRP3) as predictive factor for insulin resistance. Our study included 200 patients with PCOS, among which 108 had insulin resistance. Serum CTRP3 levels were measured using enzyme-linked immunosorbent assay. Predictive values of CTRP3 for insulin resistance was analyzed using receiver operating characteristic (ROC) analysis. Correlations of CTRP3 to insulin levels, obesity measurements and blood lipid levels were determined using Spearman's correlation analysis. Our data suggested that PCOS patients with insulin resistance had a higher obesity, lower high-density lipoprotein cholesterol, higher total cholesterol, higher insulin levels and lower CTRP3 levels. CTRP3 had a high sensitivity (72.22%) and specificity (72.83%). CTRP3 significantly correlated to insulin levels, body mass index, waist-to-hip ratio, high-density lipoprotein, and total cholesterol levels. The predictive value of CTRP3 in PCOS patients with insulin resistance was supported by our data. Our findings suggest that CTRP3 is involved in the pathogenesis and insulin resistance of PCOS, which indicates its value as an indicator for the PCOS diagnosis.

African swine fever virus infection activates inflammatory responses through downregulation of the anti-inflammatory molecule C1QTNF3

African swine fever (ASF) is the most dangerous pig disease, and causes enormous economic losses in the global pig industry. However, the mechanisms of ASF virus (ASFV) infection remains largely unclear. Hence, this study investigated the host response mechanisms to ASFV infection. We analyzed the differentially expressed proteins (DEPs) between serum samples from ASFV-infected and uninfected pigs using quantitative proteomics. Setting the p-value &lt; 0.05 and |log2 (fold change)| &gt; 1.5, we identified 173 DEPs, comprising 57 upregulated and 116 downregulated proteins, which belonged to various biological processes and pathways based on the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. The enriched pathways include immune responses, metabolism, and inflammation signaling pathways. Western blot analysis validated the DEPs identified using quantitative proteomics. Furthermore, our proteomics data showed that C1QTNF3 regulated the inflammatory signaling pathway. C1QTNF3 knockdown led to the upregulation of pro-inflammatory factors IL-1β, IL-8, and IL-6, thus inhibiting ASFV replication. These results indicated that C1QTNF3 was critical for ASFV infection. In conclusion, this study revealed the molecular mechanisms underlying the host-ASFV interaction, which may contribute to the development of novel antiviral strategies against ASFV infection in the future.

Circulating Levels of C1q/TNF-Related Protein 3 (CTRP3) and CTRP9 in Gestational Diabetes and Their Association with Insulin Resistance and Inflammatory Cytokines

Objective

Gestational diabetes mellitus (GDM) is closely related to obesity, adipose tissue, and adipokines. Adiponectin-homologous adipokines with anti-inflammatory properties, including C1q/TNF-related protein 3 (CTRP3) and CTRP9, regulate glucose and lipid metabolism, which was measured in pregnant women with GDM with the aim to assess their circulating levels and their relation with inflammatory cytokines and other biochemical data.

Methods

Serum levels of CTRP3, CTRP9, adiponectin, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were measured in 43 subjects with GDM and 42 healthy controls by enzyme-linked immunosorbent assay.

Results

Serum levels of adiponectin and CTRP3 were lower in GDM subjects than in controls, whereas CTRP9, TNF-α, and IL-6 showed higher concentrations in subjects with GDM than in controls. In the subjects with GDM, there was a significant association of CTRP3 with homeostasis model assessment of insulin resistance (HOMA-IR), body mass index, and triglycerides, whereas CTRP9 is associated with TNF-α and HOMA-IR.

Conclusion

The differences in the assessed levels of CTRP3 and CTRP9 suggest a possible relation with the pathogenesis of GDM, in particular insulin resistance, which showed significant association with both adipokines.

C1QTNF3 is Upregulated During Subcutaneous Adipose Tissue Remodeling and Stimulates Macrophage Chemotaxis and M1-Like Polarization

The adipose tissue undergoes substantial tissue remodeling during weight gain-induced expansion as well as in response to the mechanical and immunological stresses from a growing tumor. We identified the C1q/TNF-related protein family member C1qtnf3 as one of the most upregulated genes that encode secreted proteins in tumor-associated inguinal adipose tissue - especially in high fat diet-induced obese mice that displayed 3-fold larger tumors than their lean controls. Interestingly, inguinal adipose tissue C1qtnf3 was co-regulated with several macrophage markers and chemokines and was primarily expressed in fibroblasts while only low levels were detected in adipocytes and macrophages. Administration of C1QTNF3 neutralizing antibodies inhibited macrophage accumulation in tumor-associated inguinal adipose tissue while tumor growth was unaffected. In line with this finding, C1QTNF3 exerted chemotactic actions on both M1- and M2-polarized macrophages in vitro. Moreover, C1QTNF3 treatment of M2-type macrophages stimulated the ERK and Akt pathway associated with increased M1-like polarization as judged by increased expression of M1-macrophage markers, increased production of nitric oxide, reduced oxygen consumption and increased glycolysis. Based on these results, we propose that macrophages are recruited to adipose tissue sites with increased C1QTNF3 production. However, the impact of the immunomodulatory effects of C1QTNF3 in adipose tissue remodeling warrants future investigations.

The CTRP3-AdipoR2 Axis Regulates the Development of Experimental Autoimmune Encephalomyelitis by Suppressing Th17 Cell Differentiation

C1q/TNF-related proteins (CTRP) including CTRP3 are a group of secreted proteins which have a complement C1q-like domain in common, and play versatile roles in lipid metabolism, inflammation, tumor metastasis and bone metabolism. Previously, we showed that the expression of C1qtnf3, encoding CTRP3, is highly augmented in joints of autoimmune arthritis models and CTRP3-deficiency exacerbates collagen-induced arthritis in mice. However, the mechanisms how CTRP3-deficiency exacerbates arthritis still remain to be elucidated. In this study, we showed that CTRP3 was highly expressed in Th17 cell, a key player for the development of autoimmune diseases, and Th17 cell differentiation was augmented in C1qtnf3^–/– mice. Th17 cell differentiation, but not Th1 cell differentiation, was suppressed by CTRP3 and this suppression was abolished by the treatment with a receptor antagonist against AdipoR2, but not AdipoR1, associated with suppression of Rorc and Stat3 expression. Furthermore, AdipoR1 and AdipoR2 agonist, AdipoRon suppressed Th17 cell differentiation via AdipoR2, but not AdipoR1. The development of myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis was enhanced in C1qtnf3^–/– mice associated with increase of Th17 cell population. CTRP3 inhibited MOG-induced IL-17 production from T cells by affecting both T cells and dendritic cells. These results show that CTRP3 is an endogenous regulator of Th17 differentiation, suggesting that the CTRP3-AdipoR2 axis is a good target for the treatment of Th17 cell-mediated diseases.

C1q tumor necrosis factor-related protein 1: a promising therapeutic target for atherosclerosis

ABSTRACT

Atherosclerosis serves as the pathological basis of most cardiovascular and cerebrovascular diseases. C1q tumor necrosis factor-related protein (CTRP1) is a 35-kDa glycoprotein synthesized by various tissues and cells, such as adipose tissue and macrophages. As an adiponectin paralog, CTRP1 signals through adiponectin receptor 1 (AdipoR1) and participates in a variety of pathophysiological processes. Circulating CTRP1 levels are significantly increased in patients with coronary artery disease. Importantly, CTRP1 was shown to accelerate the development of atherosclerosis by promoting vascular inflammation, macrophage foam cell formation and endothelial barrier dysfunction. This review focused on recent advances regarding the role of CTRP1 in atherogenesis with an emphasis on its potential as a novel biomarker and a promising therapeutic target for atherosclerosis-related diseases.

Targeting non-coding RNAs in unstable atherosclerotic plaques: Mechanism, regulation, possibilities, and limitations

Cardiovascular diseases (CVDs) caused by arteriosclerosis are the leading cause of death and disability worldwide. In the late stages of atherosclerosis, the atherosclerotic plaque gradually expands in the blood vessels, resulting in vascular stenosis. When the unstable plaque ruptures and falls off, it blocks the vessel causing vascular thrombosis, leading to strokes, myocardial infarctions, and a series of other serious diseases that endanger people's lives. Therefore, regulating plaque stability is the main means used to address the high mortality associated with CVDs. The progression of the atherosclerotic plaque is a complex integration of vascular cell apoptosis, lipid metabolism disorders, inflammatory cell infiltration, vascular smooth muscle cell migration, and neovascular infiltration. More recently, emerging evidence has demonstrated that non-coding RNAs (ncRNAs) play a significant role in regulating the pathophysiological process of atherosclerotic plaque formation by affecting the biological functions of the vasculature and its associated cells. The purpose of this paper is to comprehensively review the regulatory mechanisms involved in the susceptibility of atherosclerotic plaque rupture, discuss the limitations of current approaches to treat plaque instability, and highlight the potential clinical value of ncRNAs as novel diagnostic biomarkers and potential therapeutic strategies to improve plaque stability and reduce the risk of major cardiovascular events.

The ABCA1-efferocytosis axis: A new strategy to protect against atherosclerosis

Atherosclerosis, a disease process characterized by lipid accumulation and inflammation, is the main cause of coronary heart disease (CHD) and myocardial infarction (MI). Efferocytosis involves the clearance of apoptotic cells by phagocytes. Successful engulfment triggers the release of anti-inflammatory cytokines to suppress atherosclerosis. ABCA1 is a key mediator of cholesterol efflux to apoA-I for the generation of HDL-C in reverse cholesterol transport (RCT). Intriguingly, ABCA1 promotes not only cholesterol efflux but also efferocytosis. ABCA1 promotes efferocytosis by regulating the release of "find-me" ligands, including LPC, and the exposure, release, and expression of "eat-me" ligands, including PtdSer, ANXA1, ANXA5, MEGF10, and GULP1. ABCA1 has a pathway similar to TG2, which is an "eat-me" ligand. ABCA1 has the highest known homology to ABCA7, which controls efferocytosis as the engulfment and processing ligand. In addition, ABCA1 can form several regulatory feedback axes with ANXA1, MEGF10, GULP1, TNFα, and IL-6. Therefore, ABCA1 is the central factor that links cholesterol efflux and apoptotic cell clearance. Several drugs have been studied or approved for apoptotic cell clearance, such as CD47 antibody and PD1-/PD-L1 antibody. In this article, we review the role and mechanism of action of ABCA1 in efferocytosis and focus on new insights into the ABCA1-efferocytosis axis and its potential as a novel therapeutic target in atherosclerosis.

The impacts of C1q/TNF-related protein-15 and adiponectin on Interleukin-6 and tumor necrosis factor-α in primary macrophages of patients with coronary artery diseases

Atherosclerosis is a progressive inflammatory disease characterized by the accumulation of lipids in the arterial wall. Inflammation plays a key role in the pathogenesis of atherosclerosis and some previous studies have shown the role of adipokines during the inflammatory process of atherosclerosis. Therefore, the present study aimed to evaluate the impacts of adiponectin and CTRP15 on inflammatory cytokines secretions from THP1 and primary macrophages.

METHODS

THP1 monocytes were differentiated to macrophages and primary monocytes were then isolated from patients with coronary artery disease and controls who were differentiated to macrophages. Macrophages were treated with LPS, LPS+adiponectin, and LPS+CTRP15.

RESULTS

Adiponectin and CTRP15 have reduced IL-6 and TNF-α secretions from LPS-induced THP1 macrophages, and the CTRP15 indicated a more potent anti-inflammatory property compared to adiponectin. In addition, adiponectin reduced cytokines' expressions and secretions in primary macrophages of both patient and control groups. However, CTRP15 has only reduced cytokines' expressions and secretions in controls and it was not able to ameliorate inflammation in macrophages of CAD patients.

CONCLUSION

The results of the present study indicate anti-inflammatory impact of adiponectin and CTRP15, while this property was stronger for CTRP15. In addition, it seems likely that anti-inflammatory CTRP15's impact on macrophages in the CAD patients was weaker than macrophages from the controls.

Effect of oxytocin on lipid accumulation under inflammatory conditions in human macrophages

INTRODUCTION AND AIMS

Oxytocin (OT) is a neuropeptide hormone secreted by the posterior pituitary gland. Deficits in OT action have been observed in patients with behavioral and mood disorders, some of which correlate with an increased risk of cardiovascular disease (CVD). Recent research has revealed a wider systemic role that OT plays in inflammatory modulation and development of atherosclerotic plaques. This study investigated the role that OT plays in cholesterol transport and foam cell formation in LPS-stimulated THP-1 human macrophages.

METHODS

THP-1 differentiated macrophages were treated with media, LPS (100 ng/ml), LPS + OT (10 pM), or LPS + OT (100 pM). Changes in gene expression and protein levels of cholesterol transporters were analyzed by real time quantitative PCR (RT-qPCR) and Western blot, while oxLDL uptake and cholesterol efflux capacity were evaluated with fluorometric assays.

RESULTS

RT-qPCR analysis revealed a significant increase in ABCG1 gene expression upon OT + LPS treatment, compared to LPS alone (p = 0.0081), with Western blotting supporting the increase in expression of the ABCG1 protein. Analysis of oxLDL uptake showed a significantly lower fluorescent value in LPS + OT (100pM) -treated cells when compared to LPS alone (p < 0.0001). While not statistically significant (p = 0.06), cholesterol efflux capacity increased with LPS + OT treatment.

CONCLUSION

We demonstrate here that OT can attenuate LPS-mediated lipid accumulation in THP-1 macrophages. These findings support the hypothesis that OT could be used to reduce pro-inflammatory and potentially atherogenic changes observed in patients with heightened CVD risk. This study suggests further exploration of OT effects on monocyte and macrophage cholesterol handling in vivo.

NPY stimulates cholesterol synthesis acutely by activating the SREBP2-HMGCR pathway through the Y1 and Y5 receptors in murine hepatocytes

AIMS

The development of non-alcoholic fatty liver disease (NAFLD) is partially attributed to disturbance in cholesterol metabolism and sympathetic overactivity. Excessive levels of the sympathetic neurotransmitter neuropeptide Y (NPY) positively correlated with both NAFLD and cholesterol accumulation. We wanted to determine, for the first time, whether NPY promotes cholesterol accumulation directly in hepatocytes and elucidate the underlying mechanism.

MAIN METHODS

In vivo, NPY was injected through the hepatic portal vein into SD rats. One hour later, serum and liver tissues were collected. In vitro, BRL-3A hepatocytes were treated with NPY, and with Y1, Y2, Y5, receptor antagonists as well as with extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) antagonist, respectively. Cholesterol content was measured by coupled enzyme method. Precursor sterol-regulatory element binding protein 2 (pSREBP2), mature SREBP2 (mSREBP2), HMG-CoA reductase (HMGCR), ERK1/2, pERK1/2, cAMP-dependent protein kinase (PKA), and pPKA protein expression levels were examined by western blotting.

KEY FINDINGS

In rats, intraportal vein injection of NPY activates pSREBP2, mSREBP2, and HMGCR protein expression, and induces hepatic cholesterol accumulation. In BRL-3A cells, we observed that NPY increases cholesterogenic protein expression and cholesterol synthesis through Y1 and Y5 receptors. This effect is mediated by the activation of the ERK1/2 signaling pathway.

SIGNIFICANCE

We demonstrated, for the first time, that NPY can activate the cholesterogenic pathway and elucidated the underlying mechanism. Thus, NPY and NPY receptors might be new targets for the treatment of NAFLD and dyslipidemia.

Increased mRNA Expression of CTRP3 and CTRP9 in Adipose Tissue from Obese Women: Is it Linked to Obesity-Related Parameters and mRNA Expression of Inflammatory Cytokines?

Background

Obesity, a medical condition with impaired adipokine secretion and function, has a detrimental effect on insulin and glucose metabolism. CTRP3 and CTRP9 are adipokines with possible roles in energy homeostasis regulation. We sought to compare CTRP3, CTRP9, and inflammatory gene expression in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from obese women who underwent bariatric surgery and non-obese women as controls.

Methods

For this study, the investigators recruited 20 morbidly obese women (BMI> 35) who qualified for bariatric surgery and 20 normal-weight women (BMI< 25) who underwent elective surgeries. Real-time PCR was performed to investigate mRNA expression of CTRP3, CTRP9, and the inflammatory genes IL1-β, IL-6, MCP-1, and TNF-α in SAT and VAT from both obese patients and controls.

Results

We observed that CTRP3 mRNA levels were significantly greater in VAT from obese patients than from controls (P< 0.0003). Also, patient group had higher levels of CTRP9 that control group (P< 0.0026). Inflammatory cytokines were markedly increased in SAT of obese patients compared to controls (P< 0.05). In addition, our results revealed a positive correlation of CTRP9 with HOMA-IR and waist circumference in VAT and CTRP3 with IL-1β, MCP-1, and TNF-α in SAT.

Conclusion

Both CTRP3 and CTRP9 expression were significantly higher in VAT from obese patients than from controls, and CTRP3 expression positively correlated with inflammatory parameters. Our findings indicate that CTRP3 and CTRP9 might be important in regulating glucose metabolism and obesity-related conditions such as inflammation.

CTRP3 Regulates Endochondral Ossification and Bone Remodeling During Fracture Healing

C1q/TNF-related protein 3 (CTRP3) is a cytokine known to regulate a variety of metabolic processes. Though previously undescribed in the context of bone regeneration, high throughput gene expression experiments in mice identified CTRP3 as one of the most highly upregulated genes in fracture callus tissue. Hypothesizing a positive regulatory role for CTRP3 in bone regeneration, we phenotyped skeletal development and fracture healing in CTRP3 knockout (KO) and CTRP3 overexpressing transgenic (TG) mice relative to wild-type (WT) control animals. CTRP3 KO mice experienced delayed endochondral fracture healing, resulting in abnormal mineral distribution, the presence of periosteal marrow compartments, and a nonunion-like state. Decreased osteoclast number was also observed in CTRP3 KO mice, whereas CTRP3 TG mice underwent accelerated callus remodeling. Gene expression profiling revealed a broad impact on osteoblast/osteoclast lineage commitment and metabolism, including arrested progression toward mature skeletal lineages in the KO group. A single systemic injection of CTRP3 protein at the time of fracture was insufficient to phenocopy the chronic TG healing response in WT mice. By associating CTRP3 levels with fracture healing progression, these data identify a novel protein family with potential therapeutic and diagnostic value. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:00-19966, 2020.

Serum levels of C1q/TNF-related protein-3 in inflammatory bowel disease patients and its inverse association with inflammatory cytokines and insulin resistance

Ulcerative colitis (UC) and Crohn's disease (CD) are two major forms of inflammatory bowel disease (IBD), which is an inflammatory disease. Studies have shown that adipose tissue and inflammation play important roles in the pathogenesis of IBD. C1q/TNF-related protein-3 (CTRP3) is a newly discovered adipokine playing a substantial role during inflammatory process, and for the first time in the present study, serum levels of this adipokine were measured in the UC and CD patients. This case-control study included 70 control, 50 UC, and 50 CD patients who were diagnosed by standard criteria. Serum levels of adiponectin, IL-6, TNF-α, TGF-β, and CTRP3 were evaluated using ELISA kits. Serum levels of IL-6, TNF-α, and TGF-β elevated in the UC and CD patients compared with the controls while adiponectin and CTRP3 diminished in the patient's groups compared with the control. Furthermore, decrease in CTRP3 serum levels was associated with the risk of UC and CD diseases. Moreover, CTRP3 indicated negative correlation with BMI, FBS, insulin, homeostasis model assessment of insulin resistance, IL-6, TNF-α, and TGF-β and also a positive correlation with adiponectin in both the UC and CD patients. For the first time, the present study demonstrated lower levels of CTRP3 in the UC and CD patients. Decreased serum levels of CTRP3 and its inverse relationship with inflammatory cytokines and TGF-β levels suggested a possible role for CTRP3 in the pathogenesis of UC and CD diseases.

Role of adipokine zinc-α2-glycoprotein in coronary heart disease

Zinc-α₂-glycoprotein (AZGP1) is a newly identified adipokine that is associated with lipid metabolism and vascular fibrosis. Although adipokines contribute to lipid dysfunction and its related diseases, including stroke and coronary heart disease (CHD), the role of AZGP1 remains unclear. In this study, the role of AZGP1 in atherosclerosis and CHD was investigated. Serum AZGP1 levels from control (n = 84) and CHD (n = 91) patients were examined by ELISA and its relationship with various clinical parameters was analyzed. Immunohistochemistry and immunofluorescence were used to detect the expression of AZGP1 and its receptor in coronary atherosclerotic arteries. THP-1 and human embryonic kidney 293 cells were used to verify its anti-inflammatory role in atherosclerosis. Serum AZGP1 levels in CHD patients were lower than controls (P < 0.01) and independently associated with CHD prevalence (P = 0.021). AZGP1 levels also inversely correlated with the Gensini score. Immunohistochemistry and immunofluorescence showed that AZGP1 and its receptor β₃-adrenoceptor (β₃-AR) colocalized in lipid-rich areas of atherosclerotic plaques, particularly around macrophages. In vitro, AZGP1 had no effect on foam cell formation but showed anti-inflammatory effects through its regulation of JNK/AP-1 signaling. In summary, AZGP1 is an anti-inflammatory agent that can be targeted for CHD treatment.

Beyond adiponectin and leptin: adipose tissue-derived mediators of inter-organ communication

The breakthrough discoveries of leptin and adiponectin more than two decades ago led to a widespread recognition of adipose tissue as an endocrine organ. Many more adipose tissue-secreted signaling mediators (adipokines) have been identified since then, and much has been learned about how adipose tissue communicates with other organs of the body to maintain systemic homeostasis. Beyond proteins, additional factors, such as lipids, metabolites, noncoding RNAs, and extracellular vesicles (EVs), released by adipose tissue participate in this process. Here, we review the diverse signaling mediators and mechanisms adipose tissue utilizes to relay information to other organs. We discuss recently identified adipokines (proteins, lipids, and metabolites) and briefly outline the contributions of noncoding RNAs and EVs to the ever-increasing complexities of adipose tissue inter-organ communication. We conclude by reflecting on central aspects of adipokine biology, namely, the contribution of distinct adipose tissue depots and cell types to adipokine secretion, the phenomenon of adipokine resistance, and the capacity of adipose tissue to act both as a source and sink of signaling mediators.

Exosomal CagA derived from Helicobacter pylori-infected gastric epithelial cells induces macrophage foam cell formation and promotes atherosclerosis

BACKGROUND

Seroepidemiological studies have highlighted a positive relation between CagA-positive Helicobacter pylori (H. pylori), atherosclerosis and related clinic events. However, this link has not been well validated. The present study was designed to explore the role of H. pylori PMSS1 (a CagA-positive strain that can translocate CagA into host cells) and exosomal CagA in the progression of atherosclerosis.

METHODS

To evaluate whether H. pylori accelerates or even induces atherosclerosis, H. pylori-infected C57/BL6 mice and ApoE^-/- mice were maintained under different dietary conditions. To identify the role of H. pylori-infected gastric epithelial cells-derived exosomes (Hp-GES-EVs) and exosomal CagA in atherosclerosis, ApoE^-/- mice were given intravenous or intraperitoneal injections of saline, GES-EVs, Hp-GES-EVs, and recombinant CagA protein (rCagA).

FINDINGS

CagA-positive H. pylori PMSS1 infection does not induce but promotes macrophage-derived foam cell formation and augments atherosclerotic plaque growth and instability in two animal models. Meanwhile, circulating Hp-GES-EVs are taken up in aortic plaque, and CagA is secreted in Hp-GES-EVs. Furthermore, the CagA-containing EVs and rCagA exacerbates macrophage-derived foam cell formation and lesion development in vitro and in vivo, recapitulating the pro-atherogenic effects of CagA-positive H. pylori. Mechanistically, CagA suppresses the transcription of cholesterol efflux transporters by downregulating the expression of transcriptional factors PPARγ and LXRα and thus enhances foam cell formation.

INTERPRETATION

These results may provide new insights into the role of exosomal CagA in the pathogenesis of CagA-positive H. pylori infection-related atherosclerosis. It is suggested that preventing and eradicating CagA-positive H. pylori infection could reduce the incidence of atherosclerosis and related events.

C1q/TNF-related protein-9 promotes macrophage polarization and improves cardiac dysfunction after myocardial infarction

The timely regulation of inflammatory M1 macrophage polarization toward regenerative M2 macrophages suggests the possibility of immunotherapy after myocardial infarction (MI). C1q/TNF‐related protein‐9 (CTRP9) has anti‐inflammatory effects and can ameliorate heart function in mice after long‐term myocardial infarction. The role of CTRP9 in macrophage polarization remains completely unclear. This study determined whether CTRP9 can preserve post‐MI early cardiac function through the regulation of macrophage polarization. In the present study, an adenovirus‐delivered CTRP9 supplement promoted macrophage polarization at Day 3 post MI and improved cardiac function at Day 7 post MI. Pretreatment with gCTRP9 promoted the M1 to M2 polarization transition and attenuated inflammation after lipopolysaccharide + interferon‐γ stimulation; the effects were partly abrogated by the adenosine monophosphate kinase (AMPK) inhibitor compound C and were obviously reinforced by pyrrolidine dithiocarbamate, a nuclear factor‐κB (NF‐κB) inhibitor. Meanwhile, CTPR9 markedly reduced the expression of toll‐like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and NF‐κB p65 phosphorylation by promoting AMPK phosphorylation in vivo and in vitro. Moreover, the competitive binding of gCTRP9 and LPS to the myeloid differentiation protein 2 (MD2)/TLR4 complex was associated with direct binding to MD2, thereby inhibiting the downstream signaling molecule MyD88. Taken together, we demonstrated that CTRP9 improved post‐MI early cardiac function, at least in part, by modulating M1/M2 macrophage polarization, largely via the TLR4/MD2/MyD88 and AMPK‐NF‐κB pathways.

Effects of LPS on the accumulation of lipid droplets, proliferation, and steroidogenesis in goat luteinized granulosa cells

Lipopolysaccharide (LPS) can cause ovarian dysfunction and infertility in mammals. The purpose of this study was to investigate the effects of LPS on the accumulation of lipid droplets (LDs), proliferation, and steroidogenesis in goat luteinized granulosa cells (LGCs). GCs isolated from the ovarian follicles were spontaneously luteinized under media with fetal bovine serum, resulting in increased progesterone and shifted shape from spherical to star with multiple prolongations. Then, LGCs were treated with LPS (0-10 μg/mL) for 0-48 hours. Oil Red O staining was performed to observe LDs accumulation and commercial kit was applied to detect intracellular triglyceride (TG) content. The cell proliferation were detected by cell counting kit-8. Expressions of cell-cycle-related genes were determined by real-time polymerase chain reaction. Estradiol (E ₂ ) and progesterone (P ₄ ) from cell supernatants were determined by enzyme-linked immunosorbent assay, and expressions of STAR, P450scc, 3β-hydroxysteroid dehydrogenase (3β-HSD) and CYP19A1 were detected by Western blot. Results showed that LPS treatment significantly increased LDs accumulation after 24 hours, and 5 μg/mL LPS increased TG content ( P < 0.05). LPS treatment for 24 hours stimulated the LGCs activities ( P<0.05), which was confirmed by the increases in the expressions of proliferating cell nuclear antigen (PCNA), cyclinB1 and cyclinD1, while 48 hours treatment had no effect. LPS treatment suppressed E ₂ and P ₄ output of LGCs ( P < 0.05). Western blot results showed that 10 μg/mL LPS decreased the protein expression of 3β-HSD in LGCs ( P < 0.05). In conclusion, LPS increased LDs accumulation and cell proliferation, and LPS-mediated P ₄ reduction could be attributed to the decreased 3β-HSD protein expression, which provide new information for the regulation of ovarian function in goats.

Microglia-Derived Adiposomes are Potential Targets for the Treatment of Ischemic Stroke

It is known that cerebral ischemia can cause brain inflammation and adiposome can serve as a depot of inflammatory mediators. In the study, the pro-inflammatory and pro-death role of adiposome in ischemic microglia and ischemic brain was newly investigated. The contribution of PPARγ to adiposome formation was also evaluated for the first time in ischemic microglia. Focal cerebral ischemia/reperfusion (I/R) animal model and the in vitro glucose-oxygen-serum deprivation (GOSD) cell model were both applied in the study. GOSD- or I/R-induced adiposome formation, inflammatory activity, cell death of microglia, and brain infarction were, respectively, determined, in the absence or presence of NS-398 (adiposome inhibitor) or GW9662 (PPARγ antagonist). GOSD-increased adiposome formation played a critical role in stimulating the inflammatory activity (production of TNF-α and IL-1β) and cell death of microglia. Similar results were also found in ischemic brain tissues. GOSD-induced PPARγ partially contributed to the increase of adiposomes and adiposome-mediated inflammatory responses of microglia. Blockade of adiposome formation with NS-398 or GW9662 significantly reduced not only the inflammatory activity and death rate of GOSD-treated microglia but also the brain infarct volume and motor function deficit of ischemic rats. The pathological role of microglia-derived adiposome in cerebral ischemia has been confirmed and attributed to its pro-inflammatory and/or pro-death effect upon ischemic brain cells and tissues. Adiposome and its upstream regulator PPARγ were therefore as potential targets for the treatment of ischemic stroke. Therapeutic values of NS-398 and GW9662 have been suggested.

Efatutazone and T0901317 exert synergistically therapeutic effects in acquired gefitinib-resistant lung adenocarcinoma cells

The development of acquired EGFR‐TKI therapeutic resistance is still a serious clinical problem in the management of lung adenocarcinoma. Peroxisome proliferator activated receptor gamma (PPARγ) agonists may exhibit anti‐tumor activity by transactivating genes which are closely associated with cell proliferation, apoptosis, and differentiation. However, it remains not clear whether efatutazone has similar roles in lung adenocarcinoma cells of gefitinib resistant such as HCC827‐GR and PC9‐GR. It has been demonstrated by us that efatutazone prominently increased the mRNA and protein expression of PPARγ, liver X receptor alpha (LXRα),as well as ATP binding cassette subfamily A member 1 (ABCA1). In the presence of GW9662 (a specific antagonist of PPARγ) or GGPP (a specific antagonist of LXRα), efatutazone (40 μmol/L) restored the proliferation of both HCC827‐GR and PC9‐GR cells and obviously inhibited the increased protein and mRNA expression of PPAR‐gamma, LXR‐alpha, and ABCA1 induced by efatutazone. LXRα knockdown by siRNA (si‐LXRα) significantly promoted the HCC827‐GR and PC9‐GR cells proliferation, whereas incubation efatutazone with si‐LXRα restored the proliferation ability compared with the control group. In addition, combination of efatutazone and LXRα agonist T0901317 showed a synergistic therapeutic effect on lung adenocarcinoma cell proliferation and PPAR gamma, LXR A and ABCA1 protein expression. These results indicate that efatutazone could inhibit the cells proliferation of HCC827‐GR and PC9‐GR through PPARγ/LXRα/ABCA1 pathway, and synergistic therapeutic effect is achieved when combined with T0901317.

Effects of exosomes from LPS-activated macrophages on adipocyte gene expression, differentiation, and insulin-dependent glucose uptake

Obesity is usually associated with low-grade inflammation, which determines the appearance of comorbidities like atherosclerosis and insulin resistance. Infiltrated macrophages in adipose tissue are partly responsible of this inflammatory condition. Numerous studies point to the existence of close intercommunication between macrophages and adipocytes and pay particular attention to the proinflammatory cytokines released by both cell types. However, it has been recently described that in both, circulation and tissue level, there are extracellular vesicles (including microvesicles and exosomes) containing miRNAs, mRNAs, and proteins that can influence the inflammatory response. The objective of the present research is to investigate the effect of exosomes released by lipopolysaccharide (LPS)-activated macrophages on gene expression and cell metabolism of adipocytes, focusing on the differential exosomal miRNA pattern between LPS- and non-activated macrophages. The results show that the exosomes secreted by the macrophages do not influence the preadipocyte-to-adipocyte differentiation process, fat storage, and insulin-mediated glucose uptake in adipocytes. However, exosomes induce changes in adipocyte gene expression depending on their origin (LPS- or non-activated macrophages), including genes such as CXCL5, SOD, TNFAIP3, C3, and CD34. Some of the pathways or metabolic processes upregulated by exosomes from LPS-activated macrophages are related to inflammation (complement activation, regulation of reactive oxygen species, migration and activation of leukocyte, and monocyte chemotaxis), carbohydrate catabolism, and cell activation. miR-530, chr9_22532, and chr16_34840 are more abundant in exosomes from LPS-activated macrophages, whereas miR-127, miR-143, and miR-486 are more abundant in those secreted by non-activated macrophages.

The adipokine C1q TNF related protein 3 (CTRP3) is elevated in the breast milk of obese mothers

Background

C1q TNF related protein 3 (CTRP3) is a relatively novel hormonal factor primarily derived from adipose tissue and has anti-diabetic properties. To determine if CTRP3 could play a role in early childhood development, the purpose of this study was to establish the presence of CTRP3 in breast milk (BM) and to determine whether CTRP3 levels were correlated with pregravid obesity status of the mother.

Methods

Breast milk was collected from breast-feeding mothers who had a pregravid body mass index (BMI) classification of normal weight (BMI 18-25 kg/m², n = 23) or obese (BMI > 30 kg/m², n = 14). Immunoprecipitation followed by immunoblot analysis confirmed the presence of CTRP3 in BM. The concentration of CTRP3 in BM samples was determined by ELISA. Additional bioactive components were also measured by commercially available assays: ghrelin, insulin, leptin, adiponectin, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and glucose. Bioactive components in normal weight and obese mothers were compared using unpaired t-test (parametric) and Mann-Whitney U-test (non-parametric), as appropriate.

Results

The primary findings of this study are that the adipokine CTRP3 is present in BM and CTRP3 levels are increased with pregravid obesity. Additionally, this study independently confirmed previous work that BM from obese mothers has a higher concentration of insulin and leptin. Further, no differences were observed in BM between obese and normal weight mothers in ghrelin, adiponectin, IL-6, TNF-α, or glucose levels.

Conclusion

This study identified a novel factor in BM, CTRP3, and showed that BM CTRP3 levels higher in obese mothers. Because of the purported insulin sensitizing effect of CTRP3, it is possible that the elevated levels of CTRP3 in the BM of obese mothers may offset negative effects of elevated leptin and insulin levels in the BM of obese mothers. Future studies will need to be conducted to determine the relevance of CTRP3 in BM and to examine the presence of other adipose tissue-derived hormonal factors.